There has been known a vehicular headlamp, which is represented by a headlight for automobiles, including a low-beam light source that illuminates the front at night, as well as a high-beam light source that illuminates farther than the low beam. The light from the high-beam light source includes a light irradiated upward from the low beam. In addition, a vehicular headlamp has been known in which such light sources are provided in a single lamp unit.
For example, Japanese Patent No. 5512183 discloses an illumination device for automobiles in which a first light source serving as a low-beam light source, a second light source serving as a high-beam light source, and a projection lens that transmits lights emitted from the first and second light sources are provided in a single lamp unit.